MOLECULAR-CLONING AND SEQUENCE-ANALYSIS OF 2 PORCINE SEMINAL PROTEINS, PSP-I AND PSP-II - NEW MEMBERS OF THE SPERMADHESIN FAMILY

Two full-length cDNAs encoding porcine seminal proteins, PSP-I and PSP -II, have been isolated from a porcine seminal vesicle cDNA library. N ucleotide sequence analysis of the 706-bp PSP-I cDNA predicts a precur sor protein of 133 amino acid residues, which includes a 21-residue si gnal peptide and a 112-residue secreted protein. On the other hand, th e complete sequence of the 686-bp PSP-II cDNA reveals a coding sequenc e for a 21-residue signal peptide and a 116-residue secreted protein. The predicted amino acid sequences agree very well with those determin ed by conventional amino acid sequence analysis. Alignment of the two cDNA sequences shows an overall 66% sequence homology throughout their entire length. However, the sequence homology is much higher in the 3 ' untranslated region (72%) than in the coding region (61%). This sugg ests that these two genes evolved by duplication and divergence from a common ancestral gene. They share about 50% amino acid sequence homol ogy and a similar overall structure with three members of the spermadh esin family.